Quantumsphere AcquisitionQUMSU
13F holders, Q1 2026 (March 31)8holders −1
1new positions
2sold out
$10.22avg. 13F price*
At the end of Q1 2026, 8 institutions reported holding Quantumsphere Acquisition Co. (QUMSU) in their 13F filings, down 1 from Q4 2025. 1 opened new positions and 2 sold out. The largest holders were Westchester Capital Management, LLC ($1.0M), GABELLI & Co INVESTMENT ADVISERS, INC. ($699K) and Gabelli Funds LLC ($591K).
- Company
- Quantumsphere Acquisition Co.
- CUSIP
- G7387B122
- Latest filing quarter
- Q2 2026
History
Number of 13F holders
Total Exit/New Position Q4 2025 → Q1 2026
| Institutions | Total Value | |
|---|---|---|
| New Positions | 1 | $2K |
| Exits | 2 | $8.4M |
All 13F filers, Q4 2025 → Q1 2026: 7,818 shares bought and 825,463 shares sold, net −817,645 shares. Counts holders who added, trimmed, opened or closed a position; split-adjusted.
Ownership 8 holders
| Westchester Capital Management, LLC | 0.05% | No change | 100,000 | $1.0M |
| GABELLI & Co INVESTMENT ADVISERS, INC. | 0.10% | No change | 67,700 | $699K |
| Gabelli Funds LLC | 0.00% | No change | 57,300 | $591K |
| HRT Financial LP | 0.00% | Reduce -3.1% | 30,138 | $304K |
| Clear Street Group Inc. | 0.00% | Add +51.1% | 22,460 | $232K |
| JPMorgan Chase & Co. | 0.00% | No change | 10,000 | $102K |
| UBS Group AG | 0.00% | Add +1.1% | 464 | $5K |
| Glazer Capital, LLC | 0.00% | New | 219 | $2K |
"% of holder's portfolio" is QUMSU's weight in each manager's 13F, not the share of Quantumsphere Acquisition Co. the manager owns.